— 79 — 
Between the time of Tournefort and Linnaeus, we still find that little pro- 
gress has been made, notwithstanding that the Lichens were receiving a little 
more attention. Most investigators at this time were interested in the question 
if the Lichens had flowers, fruit and seed, as in the case of the Phanerogams, 
whether these parts could be seen or not; that is whether the parts observed on 
Lichens could be taken as such. Micheli, an Italian botanist, believed the so- 
redia to be seeds, and the apothecium 4 , the calyx cup and floral receptacle. He 
also saw the spores, but took them to be buds. 
Dillen an English botanist, at first, was going to throw all this aside but, 
nevertheless, later expressed himself thus: that the soredia were pollen grains, 
and the apothecia, seed vessels or the seed itself. Linnaeus believed the apothe- 
cia to be male organs, and the soredia 'female organs. Heller, one of the fore- 
most lichenists of his time, and a cotemporary of Linnaeus, believed as Micheli; 
that is, that the soredia were seeds, and the apothecium a calyx cup. 
It goes without saying, that most of these ideas were not founded upon di- 
rect observations, but were merely opinions. 
As already stated, Linnaeus paid little attention to the Lichens; in his “Spe- 
cies Plantarum,’’ he mentions 86 species, although 170 were known at the time. 
The next 100 years was the era of the systematists, 1051 species of Lichens 
having been described as occurring in Germany and Switzerland alone. Discov- 
eries concerning the nature of Lichens were very few, the chief of these being 
the following: (1) The discovery of the spermagonia 5 by Hedwig (1784) — he 
believed them to be the male reproductive organs and the apothecia with their 
spores to be the female reproductive organs, and the soredia, a fertilizing element, 
or the true pollen. (2) The discovery of the gonidia 6 by Wallroth (1825), the 
most important discovery thus far made. He called them gonidia because of 
their resemblance to spores (yovY] generation, eiBoq resemblance). He made a 
careful study of the soredia, and found that they consisted of gonidia enclosed by 
a delicate network (hyphae), and held the opinion, that the gonidia, therefore 
also the soredia, could develop into new plants. He believed that the gonidia 
and spores were the only reproductive organs of Lichens. His ideas concerning 
the gonidia received general recognition. Thus we read in Lindsay (A Popular 
History of British Lichens, 1856): “They (the gonidia) may be regarded as 
intermediate in function between the vegetative and reproductive cell, assuming 
the offices and partaking the characters of both. Their great peculiarity, is the 
want of union between each other and between them and surrounding tissues. 
They frequently break through the cortical layer, appearing on its surface in 
the form of powdery masses, denominated soredia.” Lindsay, too, in speaking 
of the position of Lichens, says: “ .... by their reproductive system, Li- 
chens are closely allied to the Fungi, by their vegetative system, to the Algae, 
4 The fructification or spore-bearinng structure of the lichen. 
5 Miriute cup-shaped structures immersed in the upper surface of the thallus, appearing to the 
naked eye as minute black specks. 
6 The green cells, or Algae, found in the lichen-thallus. 
